With continuous improvement, wearable devices have been released on the market in various forms, but the wearable devices are different in characteristics of a UI due to the physical limits of the wearable device.
For example, a large-sized wearable device may include a color display, while a small-sized wearable device may have to include a small liquid crystal display (LCD) screen.
Of course, besides, the UI is mounted to the wearable device in consideration of the purposes and characteristics of the UI.
In other words, the wearable devices have different UIs in accordance with the purposes of use and characteristics thereof.
For example, there are the wearable devices such as the Apple Watch, the Samsung Gear, the Nike+, the Fitbit, etc., of which the Apple Watch has a quadrangular display, the Samsung Gear has a circular display, the Nike+ has a light emitting diode (LED) display, the Fitbit has an LCD, and, besides, there are wearable devices that provide a vibration or a sound as the UI but no display.
Like this, the UIs are different according to the wearable devices, and therefore a method (application programming interface: API) of controlling the UI varies depending on the devices, thereby causing a problem that a wearable service developer has to independently develop an API for each device.
For instance, the Apple Watch with the display is capable of giving a notice on a screen, but the Fitbit Force with no display has to use a vibration or an LED flash to give information.
Further, the wearable devices are different in not only the API but also hardware and functions, and therefore a problem arises in that an independent application needs to be additionally developed based on UI characteristics according to devices such as a device with a display, a device with vibration support, a device with sound support, etc.
Therefore, in terms of developments in UIs related to various kinds of wearable devices, a necessary API, a language, and even a use scenario have to be independently developed based on UI modules included in the wearable devices.